This invention relates to semiconductor devices, and more particularly to a semiconductor device including electrically-rewritable nonvolatile memory elements formed over a semiconductor substrate with an insulating layer interposed therebetween.
A semiconductor device equipped with an electrically-rewritable nonvolatile memory, such as a so-called EEPROM and flash memory, is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2015-103555. In the Japanese Unexamined Patent Application Publication No. 2015-103555, metal oxide nitride oxide semiconductor (MONOS) transistors are employed as memory cells (hereinafter, referred to as nonvolatile memory elements or simply, memory elements) that make up the EEPROM or flash memory. It is described that such an EEPROM or flash memory can be written and erased using Fowler-Nordheim tunneling phenomenon, hot electrons, or hot holes.
In addition, the Japanese Unexamined Patent Application Publication No. 2015-103555 discloses silicon-on-thin-buried-oxide (SOTB) transistors formed over a silicon-on-insulator (SOI) substrate.